


Her Alpha

by AceRinky (Asexual_Ravioli)



Category: Shingeki no Kyojin | Attack on Titan
Genre: ABO, Alternate Universe - College/University, F/F, Futanari, Omegaverse, PWP, Request from a Reader, Smut
Language: English
Status: Completed
Published: 2020-08-17
Updated: 2020-08-17
Packaged: 2021-03-06 00:28:00
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,558
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25954480
Author URL: https://archiveofourown.org/users/Asexual_Ravioli/pseuds/AceRinky
Summary: It was human nature, immutable fact, that two alphas could never be together; those very words had become Historia’s mantra this semester. Those and “Just be friends. Just be friends.” Those words were carrying her through.(A story in which Historia and Ymir are, together, not what they seem.)
Relationships: Krista Lenz | Historia Reiss/Ymir
Comments: 8
Kudos: 144
Collections: Finishedstoriesmine





	Her Alpha

Historia rolled the crick from her neck and re-shouldered her backpack. In her exhaustion, the long, cold walk from the biology lab to her off-campus apartment didn’t boost her energy a bit. It was pitch black out, and the slight chill of the daytime had dropped into deep, freezing night. She’d been talking with Professor Zoe for hours. Or _Professor Zoe_ had done the talking. Historia had made the mistake of asking them one question. One. But Professor Zoe found that question so insightful, so titillating, that they talked and talked, Historia suffering the consequences but also taking notes on the minutiae her professor might use as questions on their upcoming bio exam. If she had to be talked at, she’d transform the lost time into top marks.

It had been a hard start to her college career, listening to this particular professor’s excruciating, off-the-wall lectures every day, but it was worth it, Historia reminded herself. Though it was only her first year at the university, she was going to be a medical student one day; so she’d better get used to boring lectures going on ad-nauseum. The long-winded speeches of Professor Zoe would prepare her for anatomy classes and medical seminars, for being a professional with her own practice, saving lives, making a difference.

Dr. Historia Reiss, she thought to herself. Not bad.

Historia hunched her shoulders against the cold, her pace quickening. Whenever people heard she wanted to be a doctor—“timid” and “sweet” little Historia Reiss—people scoffed, laughed at her. But the truth was, Historia was in control of herself, more than anyone knew. She was more often than not a leader on group projects, because someone had to take the reins, and that someone happened to be four feet and eleven inches of pure determination, unafraid to butt heads with her lazy classmates trying to shove all the work onto her. That would not happen. They would not be holding her back.

Historia sighed to herself. It wasn’t easy, getting others to adjust their expectations of her.

The night carried a biting wind, a thin curtain of cloud blowing past an almost full moon. Her modest apartment came into view, a small, worn complex full of loud-voiced neighbors who partied more often than not. Tonight was hushed, but that could very well change as the night deepened.

She wondered if Ymir had gone to bed already. Historia bit her lip around a smile she couldn’t hide. Ymir. Her tall, muscular roommate had become her best friend at college, almost instantly. They stayed up late into the night, often talking on the couch in front of a TV series they’d long since abandoned as background noise in favor of listening to each other. After all these months, Historia felt she knew Ymir on a deeper level, but all the while there was a mystery that she couldn’t brush up against, something more, something beyond the looks of longing Historia must have imagined, projected, onto Ymir’s face as she stared back into Historia’s eyes. It didn’t matter. It was something secret she’d never get to see, one only lovers could discover. Ymir was her friend, her roommate who wouldn’t do dishes but would do sit-ups and push-ups on the living room floor for impossible lengths of time, her beautifully muscled form honed to perfection and glistening with sweat. She was a gorgeous, hardworking scholarship jock with a strong, brash personality that Historia envied and admired and grieved all at once, to the point that Historia’s stomach ached at the sight of her, at the thought of her, near constant now. Ymir: there but unreachable, there but not hers. Never, Historia thought, and she again cursed every alpha in existence. Every. Last. One.

She shook her head to rid herself of her thoughts, thoughts that could never come to fruition for one damnable, obvious reason, and dug her keys from her pocket as she passed through the main doors of the complex, trudging to their shared apartment on the second floor. She slid her key into the door and steadied herself. Ymir was probably already in bed, (she needed to wake early for baseball practice) and she wouldn’t get to talk to the ravishing brunette, their paths likely not crossing in the morning, intent as Historia was to get herself eight hours of sleep tonight. More or less, depending on how long thoughts of Ymir kept her up.

But upon opening the door, a wave of arousal nearly knocked her off her feet. Reeling, Historia stumbled back into the hall. What in the world _was_ that? The scent wrapped around her, burrowed into her lungs, prickled live over her skin. There was no question: an omega was in the apartment, an omega in heat, radiating the strongest scent Historia had ever known.

“Shit,” Historia said. Her legs trembled. She was panting as she struggled to pull the keys from the door, fingers trembling. She closed herself in the apartment and leaned heavily against the door, now trapped in the apartment with that heavy heat, nearly incapacitated with unexpected desire. It was a heat that insisted on being answered, forceful and impossible to ignore. The scent was so strong, so heady and rich, a sweet, begging, _aggressive_ scent that plunged her body into changes she could hardly control.

“Aaaah!” she cried. Her clit was already swelling, stretching in her already tight black jeans, rapidly turning into a cock. Historia moaned in equal parts pain and ecstasy, caressing her palm over the bulge.

She shut her eyes and leaned her head back against the door, breathing hard. This didn’t make sense. The only explanation was that Ymir had an omega in her room, one in an intense heat. But then where was Ymir’s alpha scent? Because there was no doubt that Historia’s rockstar athlete of a roommate was an alpha. She was tall and imposing and loud, and her muscles were jacked to hell. More than that, her very presence dominated the room—any room—she entered.

She broke out in chills as she shut her eyes and once more imagined a world where two alphas could fuck. Sadly, that world did not exist. Fucking Ymir, or being fucked by her, was not an option for this alpha. It was human nature, immutable fact, that two alphas could never be together; those very words had become Historia’s mantra this semester. Those and “Just be friends. Just be friends.” Those words were carrying her through.

Another wave of omega scent burned through the living room. Historia straightened and walked painfully to Ymir’s closed bedroom door. The heat was clearly coming from in there, and the omega was alone. Why would Ymir leave them there like that? Cursing her own inability to resist—she just had to see for herself—Historia placed her hand on the doorknob, steadied her breath, and pushed open the door.

What she saw there nearly knocked her off her feet again: Ymir stretched stark naked on her bed against the far wall, a hand between her legs, fingers working rapidly at her clit, eyes shut in concentration as she struggled to get off on her own.

Ymir. An omega.

Historia’s cock throbbed, nearly forcing her to cry out. Ymir’s toned, strong body shone with sweat. With one hand she groped at her small pert breast, fingers tracing a dark nipple. Her chest was so broad from all her work at the gym, her pecs and delts defined to the point of envy. One sinewy leg was stretched straight, the other bent with the knee facing the ceiling as Ymir bucked her hips up into her hand and huffed out a sigh. Her brow was furrowed in focus, her near black hair plastered to her forehead, framing her sharp nose, the chin Historia longed to nip at, the mouth she ached to thrust her tongue into, just once.

Now Ymir moaned, a long, frustrated sound as her hand continued to work furiously. She couldn’t do this by herself, Historia thought. This heat was too strong.

She hadn’t yet noticed Historia’s presence. Historia bit her lip, her hand straying to her crotch. She was unable to speak, gazing on that goddess body attempting to pleasure itself. Historia’s breath hitched, imagining the terrible, wonderful ways in which she could help Ymir. At last, Historia managed to pant out the words, “Ymir, you’re…an omega?”

Ymir’s eyes flew open, an almost annoyed look crossing her face as she kept her hand working, busy in her heat.

“Aah, fuck,” she moaned. “Forgot my suppressors. Y’know how it goes.”

Historia fell against the wall for support, said softly, “I don’t.”

Ymir nearly growled her next words. “Can’t you knock next time? I wouldn’t walk in on your he—”

At last Ymir’s hand froze, her eyes zeroing in on Historia’s obvious bulge.

“What was that about me forgetting my suppressors?” Historia asked. She tilted her head and sighed, already tired of the you-don’t-SEEM-like-an-alpha conversation.

“Well, fuck.” Ymir’s hand started up again, slower, and she reclined her head and shut her eyes. “Fuuuck,” she repeated in a soft moan. “Historia Reiss…an alpha. I’d never guess.”

Historia’s face flushed hot, and she lolled her head back against the wall, palming her bulge more once more. “Yes, well. You seem to be an omega. Call it even?”

Ymir scoffed and resumed satisfying herself. Historia looked and found herself unable to take her eyes away. Ymir. An omega in heat. That lean jock’s body reclined on the bed, her tanned, muscular forearm leading to a slim wrist and those slender, shapely fingers working in vain to relieve an insatiable need. Historia clenched her eyes shut and groaned aloud. This was impossible. And if it were, there was no way Ymir would want Historia to get her off.

Then Ymir made a sound between a growl and something softer, saying, “Quit touching your dick and give it to me already.”

Historia’s eyes blew wide, her erection pressing in her tight pants that much harder. “Ymir. You can’t be serious.” Hope rose in her voice.

“Yes, I’m fucking…aaaah!” Another wave of scent rolled off of Ymir, igniting an impassioned, animal instinct inside Historia’s chest.

Still Historia resisted. She couldn’t hurt her friend, couldn’t give in to her base desires. “Are you completely sure?”

“YES,” Ymir snapped. She shut her eyes and bucked her hips again. “Mmm, Historia, I need you _. Now._ ”

And that was all Historia needed to hear. If Ymir really wanted this, if she wouldn’t regret it in the morning…then it wasn’t selfish of Historia. Seeing Ymir so beside herself with desire, Historia had to help.

So she freed herself from her blouse, her tank top, then relished Ymir staring at her lacy pink bra that she knew pushed her breasts up, the soft swell enticing to any omega. Ymir’s mouth hung open, her need for release making her fingers stroke at her clit faster.

Without thinking, Historia tore off her bra. There was no going back. Her hands fumbled at the clasp of her belt, at the zipper she wrenched down. Her cock filled her panties, already dripping with precum.

Ymir sat up, eyes roving from Historia’s ample chest to her thick, barely hidden cock. “Bring that over here.”

Historia paused. That command was not the pleading, desperate voice of an omega. It was the demand of the alpha that Historia had always (wrongly) assumed Ymir to be. But now was not the time for thought, and Historia slipped from her shoes and socks and pants, walking with measured control to the edge of the bed, out of Ymir’s reach. She slowly eased her thumbs into the sides of her panties and let them fall to her feet.

“Dammit. You’re so big already,” Ymir breathed.

Historia didn’t answer but settled herself into Ymir’s lap. She fit so perfectly there, the heat of their bodies melding and burning, skin to skin, nothing left between them. She explored, kissed Ymir’s lips and roamed her hands in that dark hair as Ymir slipped her fingers over Historia’s soft waist and ran her other hand up reverently into pure strands of blonde.

“Big already?” Historia finally answered. “What else would you expect? With you giving off a _pleading_ scent like that?”

“Please,” Ymir said into her ear. “You have no idea, the scent of your rut right now.”

Historia’s face burned, and for a few hot moments, the sound of their breathing, of wet kisses, and soft sighs of pleasure were the only sounds that filled the room. Historia fingered her, Ymir crying out in desperate elation.

“Wait. I have an idea,” Ymir said, stilling Historia’s hand.

“What?” Never in all her years had an omega had a proposal in bed. Historia was about to deny her, but Ymir didn’t wait for an answer, and she sank off the bed onto her knees.

“Come,” she said, and Historia, though outraged, allowed her will to bend, planted her feet on the floor. Without asking, Ymir spread her legs, and Historia begrudgingly accepted Ymir’s mouth to her cock. She wasn’t one to be bossed around, but something in Ymir’s brazenness softened Historia’s temper.

Historia pushed Ymir’s face in harder onto her cock, leading Ymir to glare up at her, those dark eyes smoldering as her mouth, unable to retort, took on the length of Historia’s cock with ease. Historia moaned as a wave of chills rolled over her skin, electrifying her. She shouldn’t be letting an omega handle her like this, control her. But it was so fucking hot, and Ymir was clearly getting off on the role reversal, one hand busy between her legs.

Then Ymir’s hands came to tour up and down Historia’s thighs, nails raking pink lines onto her flesh. The pain lit up Historia’s insides, along with the skill Ymir was displaying in handling her cock.

Does this woman have a gag reflex? Historia wondered. She’d never had someone deepthroat her whole length like this, and Ymir seemed to do it with no trouble at all.

Experienced, Historia thought to herself, and a startling, possessive need to keep Ymir for herself flared ugly inside her. A sudden need to take this omega and own her. The words, “Mine. Ymir is mine,” emblazoned in Historia’s mind.

Her body tensed as she got more and more worked up. With one hand she grabbed Ymir’s hair and pulled. Ymir moaned around Historia’s cock. Historia didn’t bother telling her she was about to cum. When she did, she let the flow of her cum course into Ymir’s mouth, filling her. Relief flowed in Historia, and watching Ymir’s wide eyes shocked by the volume of cum pumping into her was deliciously satisfying.

Ymir pulled away, swallowing, wiping her mouth with the back of her hand.

“Good girl,” Historia said soothingly, a note of condescension making Ymir sneer.

Historia offered her no time to speak.

“On the bed. Lay,” she commanded.

Ymir jutted her chin forward. “Or what?”

“The bed,” Historia said through gritted teeth.

Ymir grinned slyly and rose her hands in the air, complying as she got to her feet. When she propped herself up by the elbows on the bed, Historia pushed her down roughly the rest of the way, by her shoulders, eliciting an angry cry of shock from Ymir. For a beat Historia stared into Ymir’s eyes, daring her to be a smart aleck one more time.

Silence. Good.

Historia spread Ymir’s legs and angled her face into her sex. She gave one last challenging glare at Ymir and, hearing no resistance, said, almost sweetly, “Ymir. Are you going to let me eat you out now?”

Ymir scoffed and glanced away. “You’d like that wouldn’t—”

“I’d love it,” Historia said, pressing one thumb hard into her clit.

“Aah!” Ymir’s body spasmed at the sudden stab of pleasure.

“Quiet now. Let me taste you.”

Ymir inhaled as if to speak, then decided against it.

Historia drew her mouth close, began to lap from the base of Ymir’s inner labia to just below her clit. Ymir groaned and shuddered, her leg muscles bunching under Historia’s hands.

“That’s a good omega,” Historia purred. “That’s good.”

Ymir moaned, partly in displeasure at being called an omega, Historia thought, and partly in ecstasy.

Historia tasted the salt of Ymir, slick with her arousal, more delicious than she’d ever imagined when alone in her own room, masturbating, pining after the beautiful jock. So many nights alone, Ymir just a wall away, seemingly miles away when Historia had so horribly mislabeled her as a fellow alpha. So much lost time, time they would now regain. Thoughts racing through her mind, she gave light, torturously slow licks to Ymir’s vulva, almost to the sweet spot. Ymir’s breathing began to grow hurried, and Historia kept to her rhythm, working with the twitches of her hips, the tensing of her thighs.

She was getting close, her sighs and grunts like music, a crescendo, to Historia’s ears, and she flicked her tongue up over the clit and began slow revolutions around it.

When she glanced up, Ymir was looking down at her with hooded eyes. Historia gave back big blue eyes, smarting with her own desire, and went back to her work of making Ymir tremble.  
“So hot for it,” Historia paused to mumble. “Tell me how much you want it.”

Ymir placed a hand on Historia’s head and pushed her face in harder. “I need it,” she moaned. “More.”

Indignation flared hot in Historia, and she knew at once she would need to correct this behavior, but for now her right hand slipped to her cock, stroking it in slow pumps as her tongue continued to work. It was beyond her wildest dreams, the two of them able to be together, Ymir luxuriating in her heat, Historia giving her pleasure, and getting her own in turn. Relaxing into Ymir’s overpowering, demanding yet needy scent, Historia shut her eyes.

Ymir’s breaths grew short and hard, her moans high and willowy. Her clutch on Historia’s hair became tighter. With this Historia slowed her tongue, Ymir positively whimpering out, “More. I’m so close. I need—”

Historia sat back on her heels and turned her head away. Ymir would learn her lesson.

“Fuck!” Ymir said. “Historia?”

Historia wiped at her mouth, hardly sparing Ymir a glance until the omega’s hands fell to her pussy, trying to stoke the arousal she’d felt coming to its peak. “Why the fuck would you—"

“Because.” Historia grabbed Ymir’s wrist tight, smiling devilishly. “You’re my omega.”

Reluctant understanding dawned in Ymir’s eyes: she would not get everything how she wanted. It was the alpha’s job to deliver pleasure. With that Historia pushed Ymir roughly to the bed and mounted her. Surprise flared in Ymir’s eyes. Historia’s cock penetrated her.

“I’m going to give it to you now,” Historia growled, “and you will take what you can get. Is that alright with you, Ymir? Tell me.”

“Aaah! Yes!” she cried out.

With a powerful pump of her hips making Ymir grip her bedsheets tight, Historia thrusted into her.

“Everyone thinks you’re an alpha,” Historia teased in a low voice. “Don’t they?”

Ymir blanched and grimaced, closing her eyes, and Historia gave another hard thrust.

“Fooled you, didn’t I?” Ymir said back in a low, mocking tone.

Historia increased her pace and gave a vicious grin. “Not anymore. I’ll see to it that you’re as submissive as they come.”

“You…” Ymir groaned, clenching her eyes tight at the indignity of being put in her place.

“You thought I was an omega,” Historia went on. “Sweet, angelic Historia. Answer me,” she said, punctuated with another thrust. She was getting close now.

“Fine!” Ymir said. “I thought…”

“What?” Historia said, curious now.

“I thought I’d never have you,” Ymir said looking her dead in the eye.

Historia was surprised but didn’t allow herself to slow. “You’re not the only one.”

“I want…” Ymir began.

Historia stopped, panting on top of Ymir, and found she really wanted to know. She wanted to give Ymir everything she could. “What do you want, Ymir?”

“I want to have you.”

Historia gave her a calculating look. “Have me? What do you call this?”

“Lay down for me,” Ymir said, a challenge with a bite to it that Historia had to respect. Coming, as it was, from a good little omega flat on her back with a cock deep inside her.

“Why should I do that?” Historia said, cupping Ymir’s chin gently. “Hm?”

“I can make you feel something new.”

But you already have, Historia thought with a gentle smile. You have no idea how much you already have.

“Fine,” she answered simply, and slowly pulled out.

They switched places, Historia taking her time in reclining on her back, resting her head on a pillow, Ymir on top in a cowgirl position..

“Well?” Historia murmured. “Make me feel.”

Ymir knelt with her legs around Historia’s sides, and eased herself onto her cock, Historia unable to resist guiding her hips with her hands. Getting her full length inside her, Ymir sighed and thrusted down.

Historia allowed her mind to rest, her heart racing at the fierce pleasure on Ymir’s face as she towered over her: long neck stretched back with her chin pointed up, eyes shut with a gorgeous, ravenous smile on her face.

“Greedy,” Historia muttered with amusement, hands idly stroking up and down Ymir’s thick, muscled thighs as she worked. Though it went against every urge in her alpha nature, Historia liked seeing Ymir be herself. She knew exactly who Ymir was: a woman of force, of dominance. If that was what she needed in bed, she couldn’t deny it. Some of the time.

Ymir placed her hands on Historia’s hips and swiveled her own, arching back in elation as the pleasure rocked her. Historia’s cock pulsed, the exquisite physical feelings rushing through it, through her body, and translating to rapturous joy in her mind.

Feel something new. A wave of confused emotions, this immense, overwhelming euphoria that should never be. Still, a sense of rightness, a heart settled in heaven or paradise, in staring up at Ymir, coupling with her. Being hers.

As Ymir’s legs tired, she planted her forearms down on either side of Historia’s head, panting over her as she continued to move. With her height, she was fully leaned over Historia, staring down with lust in her eyes.

“Well?” Ymir teased. “How do you feel?”

She’s cocky, Historia thought. In fact far too cocky for one without a cock.

“I feel you’ve had enough,” Historia rumbled. She pulled Ymir close and kissed her hard, tracing her tongue along the roof of her mouth, Ymir’s tongue lapping up, burning against hers. As Historia sat up straighter she switched her right leg to the outside of Ymir’s and transitioned her fast into missionary. Again Ymir cried out in surprise. With herself back on top, Historia relaxed into the control she felt.

“That’s better,” she lilted, her fingers stroking Ymir’s cheek. “Much better, isn’t it?” She began slow, powerful thrusts that made Ymir sound off.

“Aaaah, fuck!”

“Tell me how good,” Historia said.

“Really…really FUCKING good.”

That’s right, she thought. Really fucking good.

Historia relished seeing Ymir at this angle again, had imagined it for her roommate many times, whenever she longed for a world where two alphas could couple, where she could force Ymir on her back. As it turned out, it wasn’t so impossible, though Ymir would have to keep her non-omega behaviors in check.

She took Ymir’s breasts in her hands, Ymir responding with a soft gasp. They were so firm in her grip. Perfect breasts, belonging as much to Ymir as they did in this moment to Historia. She then traced a finger over Ymir’s collarbone before she settled both her hands onto her shoulders.

Ymir shut her eyes, Historia following suit. Their breaths panted out in tandem, rough and quick as the moment escalated. Historia felt a satisfying pressure at the base of her cock, as the knot formed, as she came closer to climax. This was it. Ymir too seemed on the verge of release, digging her nails tight into Historia’s hips and moaning wordlessly.

They came at last, together, Historia letting out a wild cry that laid itself over Ymir’s low groan of satisfaction. The knot held them together. She had never felt so joined with someone. Historia brought herself down to kiss Ymir on the neck, but her mouth opened of its own accord, and her teeth sank hard where Ymir’s slender neck joined her collar. Ymir inhaled sharply as the pain hit, clutching tighter still at Historia’s hips. Sirens wailed in Historia’s head, and she wheeled back to see the bloody mark of her teeth weeping from Ymir’s neck. Her jaw dropped at what she had done, and as she tasted Ymir’s blood on her tongue, wiping red from her mouth onto her hand, she felt at that moment she could cry.

“Oh, no! I’m so sorry,” Historia said with real regret, fingers tracing around the wound. She looked around, searching for something to stop the bleeding. “I didn’t mean to…”

Ymir smiled lazily, her fingertips lightly catching Historia’s hand, then tracing the blood. “You marked me.”

“Are you okay?” Historia said in a panic.

“Okay? I’ve wanted you to mark me since the day we met. Praying to God you were an alpha. Somehow.”

Historia laughed in spite of herself and eased herself down to her chest, her cock still hard inside of Ymir. Ymir used her strong arms to roll them to their sides.

“I was…I was so sure you were an alpha,” Historia said. “I thought, if one of us wasn’t, if we could have that, the world would be so much better. Things would be right again.”

“Lucky for you I’m ‘as submissive as they come,’” Ymir grumbled.

Historia smiled and nuzzled her face against Ymir’s. “You’re so much better than an omega. You’re you.”

“Damn straight.”

A pause. Then Historia chuckled to herself, and Ymir gave her a look. “What’s so funny?”

“You’re mine,” Historia laughed, kissing her fiercely. “My omega.”

Ymir sighed in resignation. “I’m yours? I’ll have to adjust to that.”

“Yes. Yes, you will,” Historia said sternly.

“But there’s something you’ll need to adjust to,” Ymir growled, and Historia knew what was coming. With a quick motion, Ymir rolled them back into cowgirl, pinning her down. “Being _my_ alpha.”

Historia blushed hard and turned her face away, schooled her voice before she said, “I might allow that.”

Ymir smirked down at her. “Mm. You just need practice. Lots and lots of practice.”

Historia gave a half smile. “And you’ll give it to me?”

“And you’ll like it,” Ymir whispered with a final kiss.

Historia shuddered and let herself be used, prepared her body to be throttled by Ymir on top, until Historia got ideas to rail Ymir, and they’d switch and switch and make love into the morning as much as they could. As much as lovers could, again and again and forever. It dawned on her that, no, she wasn’t going to get any sleep tonight. Because the world had righted itself: Ymir was her omega, and Historia was her alpha.

**Author's Note:**

> This was a request from an anon!
> 
> [For more lesbianism, please check out my tumblr :)](https://acerinky.tumblr.com/)


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